'04 Forester sulfer smell (YUCK!)

[jeremynd01]

Hello all!

 

My wife and I have an '04 Forest that STINKS (literally, not mechanically. Well, maybe mechanically...). The exhaust generates the worst rotten egg smell one can imagine. If it weren't for the dumb auto-dimming rear view mirror, perhaps I wouldn't have to look at all the crinkled noses in traffic behind me!

 

I've had it in to the dealer, and they blame it on Ohio's crummy, high-sulfer content gas. They actually said, "Your car's an LEV (low emmisions vehicle). That's why it smells so bad." Well, paint me crazy, but shouldn't an LEV NOT smell like butt crack?

 

From what I can gather, their excuse is that the car conforms to California emmissions, and so they assume the use of low-sulfer California gas. Which is to say it's been engineered to do nothing about sulfer emissions.

 

I think this is a big load of bull butter. I asked if this is common, and they said they get this complaint all the time. I figured if that were true, and if every Forest in the 49 states that are not California smell bad, there should be people griping about it all over Google. I see plenty of people complaining about Toyota 4Runners and old Chevy's, but very few Subaru gripes.

 

I've read a lot about emissions and such, and many folks say funny exhaust smells are typically caused by catalytic converter failure or a bad oxygen sensor. I see that the cat'converter reduces NOx to nitrogen and oxygen:

 

2NO => N2 + O2 or 2NO2 => N2 + 2O2

and that it oxidizes carbon monoxide to the lesser evil, carbon dioxide:

 

2CO + O2 => 2CO2

but I don't see any thing to substantiate the claims that the rotten egg smell means the cat'converter is working (i.e. producing dihydrogen sufide), or that the opposite is true - a failed cat doesn't crack a suflide. In fact, I don't see any mention of sulfer at all, and I'm not a very good chemist.

 

Anyone out there know more about catalytic converters, maybe clear this up? What about the theory that the car running at a bad fuel mixture (due to a faulty oxygen sensor) would cause it?

 

If you're a Forester owner and do (or do not!) have this problem, please, chime in! I'd like to see how alone in this I am.

[friendly_jacek]

Well I had it in my 03 corolla; it was a common problem in those 03-04 toyotas while brand new and Toyota kept saying it was normal. I and other owners lobbied the EPA hard and toyota had to come up with TSB offering a replacement of cat and reprogram of ECU.

 

 

To answer you chemistry questions, sulfur compounds in gas (unregulated in USA outside CA before 2004) are burned to SO2. This is “normal” (but contributes to acid rain, asthma, and other good things). In lean conditions and high cat temps, it can be oxidized catalytically to SO3 which can actually deposit in and poison the cat. However, rich conditions will allow for reducing SO3 to H2S producing the bouts of smell you keep enjoying (“self cleaning”).

 

In short, the problem is multifactorial:

 

 

 

• High sulfur in gas.
  
• Frequent lean and especially rich conditions.
  
• Some cats are more effective in catalyzing these sulfur reactions, I understand nickel-free cats used in some parts of Europe and/or in some brands (Toyota) are the worst.
  

So, you basically need to

 

 

• stop using the offending brand of gas with high sulfur
  
• check for proper functioning of the emission system (O2 sensors, ECU, cat, ect.). However, subarus are notorious for running rich a lot by design.
  
• Maybe replace cat as a last resort.
  

I am surprised you have these problem since beginning in 2004 lower surfur gas was phased in entire USA under federal legislation. Are you using some kind of cheapo, bootleg gas imported from China?

Keep us posted.

[jeremynd01]

What - there's CHEAP bootleg gas from China? Where can I get some? Will it be less than $2/gal?? Just kidding!

 

I fill up at the BP at the end of my street. When I first noticed the stench in December, I thought it might be a bad tank of gas I got on the highway during holiday travel. At the suggestion of the dealer I tried other brands, other stations, and even filled up out of state once. Nothing made the smell subside, and, quite frankly, I don't think I'm going to drive out of my way to get gas when hundreds of millions of cars on the road don't have this problem (so it's not something beyond the scope of repair).

 

Thank you immensely for the chemistry lesson! I was tired of reading posts by wanna-be grease monkeys that contradicted each other (i.e. "The rotten egg smell means the cat is working!" versus "The rotten egg smell means the mixture is lean/rich!" versus "Rotten egg smell? I bet you cat is hotter than the surface of the sun"). I think a trip to the dealer for a new O2 sensor is in order.

 

I'm also going to have a look for the federal regulations you mentioned. The Subaru dealer slipped me a printout of some 2000 data that showed gas in NY at 150+ ppm of sulfer content, while CA is regulated to <30 ppm. I'd like to find out nationwide stats with these new regs.

 

I might also have a chat with the EPA and Ohio's sulfer emissions guy, who I found online the other day. I was afraid these folks would be too busy with coal plants and steel mills to bother with a few million Subaru bustling around, stinking up the place, but the success of the Toyota owners has heartened me. Thanks!

[Nug]

I'd have a hard time admitting that my car smells like butt crack.

[Gnuman]

I'd have a hard time admitting that my car smells like butt crack.

 

I'd have a hard time admitting that I knew what butt-crack smelled like

[friendly_jacek]

What - there's CHEAP bootleg gas from China? Where can I get some? Will it be less than $2/gal?? Just kidding!

 

I fill up at the BP at the end of my street. When I first noticed the stench in December, I thought it might be a bad tank of gas I got on the highway during holiday travel. At the suggestion of the dealer I tried other brands, other stations, and even filled up out of state once. Nothing made the smell subside, and, quite frankly, I don't think I'm going to drive out of my way to get gas when hundreds of millions of cars on the road don't have this problem (so it's not something beyond the scope of repair).

 

Thank you immensely for the chemistry lesson! I was tired of reading posts by wanna-be grease monkeys that contradicted each other (i.e. "The rotten egg smell means the cat is working!" versus "The rotten egg smell means the mixture is lean/rich!" versus "Rotten egg smell? I bet you cat is hotter than the surface of the sun"). I think a trip to the dealer for a new O2 sensor is in order.

 

I'm also going to have a look for the federal regulations you mentioned. The Subaru dealer slipped me a printout of some 2000 data that showed gas in NY at 150+ ppm of sulfer content, while CA is regulated to <30 ppm. I'd like to find out nationwide stats with these new regs.

 

I might also have a chat with the EPA and Ohio's sulfer emissions guy, who I found online the other day. I was afraid these folks would be too busy with coal plants and steel mills to bother with a few million Subaru bustling around, stinking up the place, but the success of the Toyota owners has heartened me. Thanks!

 

Good luck,

BTW this is the Toyota's TSB:

http://www.autosafety.org/Toyota%2003-04%20Corolla%20Catalyst.pdf

Notice that even toyota's house chemists got it wrong and called the odor: "sulfur dioxide".

This is the response I got from EPA, if it may be helpful for your quest:

 

Mr. XXX:

 

Your e-mail has been forwarded to me for response.

 

Over the past 13 years or so, I have handled citizen complaints to EPA

 

on "rotten egg" smell from vehicles. In recent months, we have received

 

a significant increase in complaints about this problem in late model

 

vehicles (primarily 2003) produced by certain manufacturers. One of

 

them is Toyota. In fact, yours is the second complaint I have received

 

on a 2003 Toyota today. Most manufacturers are not experiencing a

 

problem with "rotten egg" smell.

 

 

 

This problem occurs predominantly in vehicles with very efficient

 

catalysts running on gasoline with relatively high sulfur levels, which

 

is sold throughout most of the U.S except California. It is likely that

 

only a small fraction of Toyota vehicles are experiencing the problem.

 

The manufacturing of vehicles and catalysts always has production

 

tolerances. Only certain vehicles probably at the tail end of the

 

ranges for whatever catalyst parameters and air:fuel ratio factors favor

 

hydrogen sulfide formation are having this problem. The odor is often

 

strongest in new vehicles with low mileage, and usually diminishes as

 

the catalyst ages.

 

 

 

As you have already surmised based on your own research, manufacturers

 

who are not experiencing the problem add nickel to their catalyst

 

formulation. We have been told by several manufacturers that there are

 

concerns in some European countries about handling nickel in the

 

catalyst manufacturing process because some compounds containing nickel

 

have adverse health effects.

 

 

 

EPA is very concerned about this problem. We are in the process of

 

meeting with all the major manufacturers, and are working with the ones

 

experiencing the problem to obtain a commitment from them to correct it.

 

 

 

Technical health effects information on hydrogen sulfide can be found on

 

the internet, on EPA's Integrated Risk Information System (IRIS). Here

 

is a link to this information:

 

 

 

http://www.epa.gov/iris/subst/0061.htm

 

 

 

I hope you find this information helpful. Please call me or e-mail me

 

if I can be of additional assistance.

 

 

 

Rich Cook

 

Environmental Scientist

 

U.S. EPA

 

Office of Transportation and Air Quality

 

2000 Traverwood Drive

 

Ann Arbor, MI 48105

[brus brother]

Several years ago, a friend returned a car under the lemon law after Subaru failed to remedy the same situation.

Get it all documented.

It sounds like you are not willing to own the "runt" of the litter.

Make them change the CAT, O2 sensor, front bumper, CD player (if equipped), whatever, to make your car perform as any other on the lot.

Alternatively, park your car outside the dealership on any given day with a sign in the window advertising the aforementioned aromas.

[Soobadooba]

We have an '04 Forester and get no rotten egg smell. It is the turbo model, though. I don't know how much of a difference that would make. I also have no idea what the sulfur content of the gas is here to compare to yours.

[wkoepp]

We have a '04 Forester (no turbo) and it emits no sulpher smells here in California, however our '97 Toyota 4-Runner does smell, I don't put the rear window down under 20 mph or the smell enters the cabin.

[jeremynd01]

Thanks for chiming in, all.

 

I looked up those EPA gas standards '_jacek mentioned. I found them under the title "Tier 2/gasoline sulfur," which passed in 1999 and phases into full effect in 2007. Here's the link:

 

http://www.epa.gov/otaq/tr2home.htm

 

One of the documents breaks the sulfur content of gas down like this (all numbers are parts per million (ppm)):

Gasoline Suflur Standards

Date Max RefineryAvg. CorperateAvg.

2004 300 120? 120

2005 300 30 90

2006 80 30 30?

 

I don't know why some dates list a separate "corporate average" from "refinery average," but there's lots of talk in the document about applying for relief and getting credits for cleaning up early, so there's still a chance the levels are higher.

 

PS. Thanks, Nug and Gnuman, for pointing out my fetish.